Resilient tuning pin



Nov. 10, 1964 c. w. ANDERSEN 3,156,151

RESILIENT TUNING PIN Filed June 19, 1963 g4 45 16 J04 J5 INVENTOR United States Patent i 3,156,151 RESiLlENT TUNKNG HN Clifiord W. Andersen, De Kalb, ilk, assignor to The Wurlitzer Company, Chicago, ilk, a corporation of Ghio Filed June 19, 1%3, Ser. No. 2%,089 6 Claims. (Cl. 34=-2il1) This invention relates generally to pianos and analogous musical instruments and relates more particularly to the piano component known as a tuning pin.

A common problem with conventional, stringed pianos involves loosening of the tuning pins and concomitant relaxation of the string which is attached to the pin. Such relaxation, of course, destroys the proper tune of the string. Heretofore, tuning pins have been fashioned as solid elements; and the problem of loosening has been attacked by using auxiliary sleeve bushings, oversized pins or various chemical formulations. These expedients have proved to be inconvenient and have not provided a total solution to the problem.

Therefore, an important object of the present invention is to provide a tuning pin which establishes a tight fit in a piano frame without the need for adjunct structure or compositions.

A more general object of the invention is to provide a new and improved tuning pin arrangement.

Another object of the invention is to provide a radially resilient tuning pin.

These and other objects and features of the invention will become more apparent from a consideration of the following disclosure.

A tuning pin structure in accord with the invention includes a tubular body of resilient material which is formed with a lateral opening, longitudinally extending slot. The tubular body of the tuning pin structure is thus able to react resiliently to radial compression for wedged engagement into a receiving bore fashioned in a piano frame. The tuning pin structure of the invention also includes a tool-engageable formation on one end of the tubular body.

In order that the principles of the invention may be readily understood, a single embodiment thereof, but to which the application is not to be restricted, is shown in the accompanying drawing wherein:

FIG. 1 is a central sectional view taken through a piano to show the operating elements thereof, including a tuning pin that is constructed in compliance with the invention;

FIG. 2 is an enlarged sectional view taken substantially along the line 22 of FIG. 1; and

FIG. 3 is an enlarged perspective view of the tuning pin of FIG. 1.

Referring now in detail to the drawing, specifically to FIG. 1, the piano structure indicated generally by the numeral 10 will be seen to include a keyboard 12, a string frame 14 and an action assembly 16. The keyboard 12 includes a keybed 18, a keyframe 2t) and a number of 1 key levers such as key lever 22. The keyframe 26 is mounted on the keybed l8 and includes a balance rail 24 into which upstanding balance rail p ns 26 are inserted. Each key lever 22 is slotted to receive a balance rail pin 26 for fulcruming the key lever; and the keyframe also includes a back rail 28 to which a felt pad 3%) is attached to act as a rest for the rear end of the key lever 22.

Depression of the forward end of piano key lever 22 is arranged to cause a striking of the corresponding piano string through one of the individual action mechanisms incorporated in the action assembly 16. The individual action mechanism associated with the key lever 22 is indicated generally by the numeral 32. A main rail 34,

3,156,151 Patented Nov. 10, 1964 ice a hammer rail 36 and a regulating rail 38 extend through the body of the piano 10 to support and cooperate with each of the action mechanisms 32, action brackets 46 and tubular action spacers d2 being used to mount the rails 34, 36 and 38 in place.

The action mechanism 32 includes a hammer 44 that is mounted to a butt knuckle 46 by a hammer shank 48, the butt knuckle 46 being pivotally mounted to the main rail 34 by a butt flange 5%). Depression of the piano key lever 22 is arranged to actuate hammer 44 by means of a sticker or abstract 52 that is detachably aflixed at one end of the key lever 22 by means of a coupling arrangement 54. The sticker 52 is swingably mounted at its other end to a whip 56, and the whip 56 is pivotally mounted to the main rail 34 by a whip flange 58. A fly or jack 6i) is pivotally mounted to the whip 56 by a fly flange 62. The head of fly 60 engages a cushioned surface on the butt knuckle 46, and a regulating rail button 64- is mounted to regulating rail 38 for cooperative engagement with a heel portion 66 of the fly 6%. Upon depression of the piano key lever 22, the sticker 52 rises with a resultant pivoting of the whip 56. Engagement of the heel portion 66 of the fly with the regulating rail button 64 impells the hammer 44 into percussive engagement with a corresponding piano string 68 that is mounted on the piano frame 14.

A partially felt-surfaced backcheck 70 is fastened to the whip 56 in upstanding relationship by means of a backcheck wire or rod 72; and a cooperatively felt-surfaced catcher 74 is secured to the butt knuckle by means of a catcher stem or shank 76 which radiates from the butt knuckle. The action mechanism 32 also includes a metal spoon 78 which is aflixed to the whip 56 in upstanding relationship, being disposed on the end of the whip which is opposite the connection with abstract 52. Upon actuation of the whip 56 by means of the key lever 22, the spoon 78 contacts the lower, felt surfaced end of a damper lever 86?, damper lever 89 being swingably mounted to the main rail 34 by means of a damper lever flange 82. The spoon '78 is specifically arranged to operate damper lever 80 so as to retract a damper head 84 from contact with the piano string 68 immediately in advance of the hammer 44 striking the string.

The piano string frame 14 is ordinarily fabricated from steel and includes an upper frame section 86 and a lower frame section 88 which is spaced from the upper frame section. A hitch pin 96 is mounted in the lower frame section 83 and a bore 92 is fashioned in the upper frame section 86 spaced from the hitch pin to receive a tuning pin indicated generally by the numeral 94. The piano string 63 includes a loop end 96 which is fitted over the hitch pin i l), the opposite end of the piano string 68 being attached to the tuning pin 94 in a manner to be described more fully hereinafter. The upper frame section $5 is provided with an upper frame bridge 98, and the lower frame section 88 is provided with a lower frame bridge 1% which are appropriately spaced apart to define the vibrating length of the piano string 68. Advantageously, an agraffe 162 contacts the piano string68 between the tuning pin 94 and the upper frame bridge 98 to prevent vibration of the string between these two latter points. A soundboard 104 is aligned behind the piano string frame 14 to span the space between the upper and lower frame sections thereof; and a soundboard bridge 1% is mounted to the soundboard 104 in physical contact with the piano string 68 to couple the vibration of the string to the soundboard. Bridge pins 1% are mounted on the soundboard bridge 106 on oppo site lateral sides of the piano string 68 to preserve the lateral positioning of the string and prevent its vibrational contact with adjacent strings.

Referring now to FIGS. 2 and 3 for a detailed description of the features of the invention, the tuning pin dd will be seen to comprise a tubular body 114i which is fashioned of a resilient material such as spring steel. In order to permit the wall of body 110 to react resiliently to radial compression, the body Ilill includes a laterally opening, longitudinally extending slot 112. in the illustrated embodiment, the slot 112 extends the entire length of the tuning pin; and in compliance with a feature of the invention, the slot 112 is arranged to have a length at least equal to the depth of the bore which is fashioned in the cooperating piano string frame for receipt of the tuning pin 94. The wall of the tuning pin may thus expand in radially resilient manner into tightly fitting relationship with the wall of the bore whereby to mount the tuning pin in substantially non-rotatable fashion.

The tuning pin d4 also includes a tool-engageaole formation 114 on one end of the body 11d; and the toolengageable formation 114 takes non-round section to facilitate its being gripped by a wrench. In order to provide an attachment situs for the free end of piano string 68, the tuning pin 94 is provided with a radially opening aperture 116 away from the slot 112. The aperture 116 is located angularly from the slot 112 by ninety degrees in the illustrated embodiment; and while the aperture 116 need only open through one side of the tuning pin, it advantageously opens from diametric sides thereof. Thus, the free end 113 of the piano string 68 may be passed through the aperture 116 and the tuning in $4 rotated to bind the piano string to the tuning pin. The aperture 116 is'located generally at the juncture between the body 11% and the formation 114 so that the wrapped portion of the string does not interfere with the resilient action of the walls of the tubular body 110.

Provision of a tuning pin with the structure and arrangements described promotes a wedged engagement of the body of the pin in the receiving bore of the string frame, and the radial resiliency of the body of the tuning pin substantially prevents the pin from working loose in the bore. Proper tuning of the piano string 68 is thus preserved and extended, rendering a piano equipped with the instant tuning pins more satisfactory to the user.

The specific example herein shown and described is to be considered as being primarily illustrative. Various changes in structure will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A tuning pin for insertion in a bore fashioned in a piano frame to form a mounting'situs for one end of a piano string, said tuning pin comprising: a tubular body fabricated of resilient material which is shaped to dispose confronting edges in spaced relationship for establishing a laterally opening, longitudinally extending slot, said material forming a continuous connection between said edges away from said slot for establishing an elongated hin e axis extending longitudinally of said tubular body, whereby the wall of said body reacts resiliently to radial compression for wedged engagement of said body in a said bore; and a tool-engageable formation on one end of said body. 1

2. A tuning pin for insertion in a bore fashioned in a piano frame to form a mounting situs for one end of a piano string, said tuning pin comprising: a tubular body a laterally opening, longitudinally extending slot and said material forming a continuous connection between said edges away from said slot for establishing an elongated hinge axis extending longitudinally of said tubular body, whereby the wall of said body reacts resiliently to radial compression for wedged engagement of said body in a said bore, said body having a radially opening aperture away from said slot adapted to receive the free end of a piano string in attachment of said string to said tuning pin; and a tool-engageable formation on one end of said body.

3. A tuning pin according to claim 1 wherein said tubular body is fabricated from spring steel.

4. in a piano structure, the combination comprising: string frame means having a hitch pin and a bore spaced from said hitch pin to receive a tuning pin; a tubular tuning pin of resilient material disposed in said bore with an interference fit therebetween, said material being shaped to dispose confronting edges in spaced relationship for establishing a laterallyopening slot, and material forming a continuous connection between said edges away from said slot for establishing an elongated hinge axis extending longitudinally of said tubular member, whereby the wall of said pin radially resiliently expands into tightly fitting relationship with the wall of said bore for mounting said pin in substantially non-rotatable manner; and a piano string stretched between said hitch pin and said tuning pin.

5. In a piano structure, the combination comprising: string frame means having a hitch pin and a bore spaced from said hitch pin to receive a tuning pin; a tubular' tuning pin of resi ient material disposed in said bore with an interference fit therebetween, sad material being shaped to dispose confronting edges in spaced relationship for establishing a laterally opening slot having a length at least equal to the depth of said bore, said material forming a continuous connection between said edges away from said slot for establishing an elongated hinge axis extending longitudinally of said tubular member, where by the wall of said pin radially resiliently expands into tightly fitting relationship with the wall of said bore for mounting said pin in substantially non-rotatable manner; and a piano string stretched between said hitch in and said tuning pin. I

6. In a piano structure, the combination comprising: string frame means having a hitch pin and a bore spaced from said hitch pin to receive a tuning pin; a tubular tuning pin of spring steel disposed in said bore with an interference fit therebetween, the material of said pin being shaped to dispose confronting edges in spaced relationship for establishing a laterally opening slot, said material forming a continuous connection between said edges away from said slot for establishing an elongated hinge axis extending longitudinally of said tubular body, whereby the wall of said pin radially resiliently expands into tightly fitting relationship with the wall of said bore for mounting. said pin in substantially non-rotatable manner; and a piano string stretched between said hitch pin and said tuning pin.

References Qited in the file of this patent UNITED STATES PATENTS 295,048 Patterson Mar. 11, 1884 903,086 Heginbothorn Nov. 3, 1908 1,233,552 Clauder et al. luly17, 1917 2,075,901 Schulze Mar. 23,1937 2,620,701 Massey Dec; 9, 1952 

1. A TUNING PIN FOR INSERTION IN A BORE FASHIONED IN A PIANO FRAME TO FORM A MOUNTING SITUS FOR ONE END OF A PIANO STRING, SAID TUNING PIN COMPRISING: A TUBULAR BODY FABRICATED OF RESILIENT MATERIAL WHICH IS SHAPED TO DISPOSE CONFRONTING EDGES IN SPACED RELATIONSHIP FOR ESTABLISHING A LATERALLY OPENING, LONGITUDINALLY EXTENDING SLOT, SAID MATERIAL FORMING A CONTINUOUS CONNECTION BETWEEN SAID EDGES AWAY FROM SAID SLOT FOR ESTABLISHING AN ELONGATED HINGE AXIS EXTENDING LONGITUDINALLY OF SAID TUBULAR BODY, WHEREBY THE WALL OF SAID BODY REACTS RESILIENTLY TO RADIAL COMPRESSION FOR WEDGED ENGAGEMENT OF SAID BODY IN A SAID BORE; AND A TOOL-ENGAGEABLE FORMATION ON ONE END OF SAID BODY. 